Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1997-11-10
2001-06-26
Marcelo, Melvin (Department: 2663)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
Reexamination Certificate
active
06252880
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to buffered distributors, more specifically to full-duplex buffered distributors sending data packets between network nodes.
2. Background Art
Repeaters are typically used as an interconnection between network nodes, for example network stations serving as data terminal equipment (DTE) on different network media. Repeaters provide the advantage of extending the physical distance between network nodes by receiving the data packet from one network media, reconditioning the physical signal, and outputting the data packet to a second network media.
Certain vendors have proposed a buffered distributor, also referred to as a full-duplex repeater, as a viable alternative to a half-duplex repeater. Specifically, the buffered distributor includes a number of network ports, where each network port is configured for full-duplex communication with a corresponding network node. Each network port includes a receive first in-first out (FIFO) buffer, and a transmit FIFO buffer. The buffered distributor also includes a repeater core, also referred to as a “backplane,” that distributes a data packet stored in one of the receive FIFO buffers to the other network ports. Specifically, a receive FIFO buffer outputs a stored data packet to the other network ports by gaining access to the backplane. Access to the backplane may be implemented either by CSMA/CD logic, where the Receive FIFO buffers contend for access to the backplane using a zero topology collision domain (using CSMA/CD logic), or another arbitration scheme such as round-robin.
The above-described buffered distributor also includes a flow control mechanism according to IEEE 802.3x, where the repeater core will generate a PAUSE frame when a predefined threshold is reached in the one of the receive FIFO buffers. Specifically, a network port having a detected congestion condition (i.e., stored data exceeding the predefined threshold) in its corresponding receive FIFO buffer will output a MAC control frame carrying a predetermined PAUSE interval into the corresponding transmit FIFO buffer. The network node in communication with that network port, having received the MAC control frame, will suspend transmission for the predetermined PAUSE interval, enabling the repeater core to remove packet data from the congested receive FIFO buffer.
A problem encountered in use of a buffered distributor in a workgroup environment is that one or more servers may be connected to the buffered distributor along with several clients. In addition, one of the ports may be connected to a router or switch. In such an environment, the router port (or switch port) will see all the frames that are communicated between the client and the server. Hence, the router port (or switch port) may be unnecessarily used to transmit non-relevant traffic to the router (or switch). Moreover, resources in the router (or switch) are wasted in reading and discarding the received data frames that are intended for the client and server.
SUMMARY OF THE INVENTION
There is a need for an arrangement for interconnecting network nodes using a buffered distributor, where traffic to a predetermined network node can be limited based upon the destination address of data frames received by the buffered distributor.
There is also a need for an arrangement in a workgroup environment that prevents client-server traffic from being unnecessarily transmitted to different network nodes, such as a switch or a router.
There is also a need for an arrangement in a buffered distributor that avoids unnecessary transmission of data packets to a predetermined network node to prevent discarding of frames at the predetermined network node.
These and other needs are attained by the present invention, where a buffered distributor includes a filter that selectively supplies a received data packet to a predetermined network node based on the destination address of the received data packet and the network address of the predetermined network node.
According to one aspect of the present invention, a buffered distributor comprises a plurality of network ports serving respective network nodes, each network port comprising a receive buffer for storing a first data packet received from the corresponding network node and a transmit buffer for storing a second data packet to be transmitted to the corresponding network node, and a distribution core comprising a filter for selectively supplying the first data packet received from the corresponding network port to a selected one of the remaining network ports based on a destination address of the first data packet and a network address of the network node corresponding to the selected one network port. The selective supply of the first data packet to the network port corresponding to the selected network port based on the destination address and the network address of the network node ensures that the buffered distributor does not output non-relevant data to the selected network node. Hence, a buffered distributor may be used in a workgroup environment, without burdening router or switch resources with client-server traffic.
Another aspect of the present invention provides a method in a buffered distributor comprising storing a network address of a predetermined network node, receiving a received data packet on one of a plurality of network ports in the buffered distributor, determining a destination address of the received data packet, and selectively transmitting the received data packet to the predetermined network node from the corresponding network port based on the destination address relative to the stored network address. The selective transmission to the predetermined network node minimizes non-relevant traffic to the predetermined network node in order to prevent wasting resources at that predetermined network node. Hence, the buffered distributor can be used to transmit data packets between network nodes, where selective transmission is performed on the network port corresponding to the predetermined network node to avoid unnecessary data traffic.
Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.
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Hanna Ganatios Y.
Kalkunte Mohan V.
Advanced Micro Devices , Inc.
Kwoh Jasper
Marcelo Melvin
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